The matting process for combining scenes has been used in the motion picture industry for nearly as long as motion pictures have been known. Various names have identified this process; i.e., the "Dunning Process," "Blue Backing," "Sodium Vapor Lighting Matte," and others.
In practice, the foreground action is photographed using one of the above processes and then a suitable background is photographed separately. The foreground has usually consisted of actors in a studio, while the background has been a scene from a foreign land, a forest, or some other scene that would be difficult to construct in the studio.
The two images have been subsequently combined into a single image by using an optical printer.
The two negatives are photographed separately. Thus, any relative motion between the two cameras during the photographing process will be easily seen and will be detrimental in the attempt to achieve realism.
As a result, most matte shots are rather static in nature. The action is limited to movements of a foreground object or persons, while the cameras remain stationary.
Television production has been similarly restricted.
In television the matting process is all-electronic; through the use of "Chroma-Key," "Technimatte," "Image-Matte," or a similar process.
The rigid technical constraints remain. When the two cameras are matted in registration, any movement of one camera must be precisely duplicated by the other camera, or a disturbing relative motion results.
A system known as "Magicam" has been disclosed in U.S. Pat. Nos. 3,902,798 to Trumbull et al, Sept. 2, 1975, and 3,914,540 to Slater, Oct. 21, 1975; and in the A.S.C. journal, "American Cinematographer," Vol 56, No. 1, January 1975, page 34, et seq.
This system uses exclusively a servo-motor-amplifier control to obtain synchronization of camera movements. A special floor is used for the foreground camera that is smooth to 1/32 inch (0.8 millimeter) over the large area desired. A special sensored camera dolly is used.
This invention pertains to a method and an apparatus for synchonizing two or more cameras with respect to motion and optical characteristics.